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Stockholders' Equity - Summary of Anti-Dilutive Options Excluded (Details) - $ / shares
3 Months Ended 9 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2019
Sep. 30, 2018
Stockholders' Equity Note [Abstract]        
Options to purchase shares of common stock (in shares) 553,366 3,069,590 460,824 3,194,684
Weighted average exercise prices of options (in dollars per share) $ 27.59 $ 27.51 $ 27.55 $ 27.51